Abstract : Selected navigation structures are periodically monitored under the periodic Inspections work unit of the Monitoring Completed Navigation Projects research program. Monitoring is done to gain an understanding of the long term structural response of unique structures to their environment. Periodic data sets are used to improve knowledge in the design, construction, and maintenance of both existing and proposed projects. This report is the first in a series that will track the long term structural response of the Ofu Harbor breakwater, American Samoa, to its environment. Data from limited ground based surveys, aerial photography, and photogrammetric analysis were obtained to establish base level conditions for the Ofu Harbor breakwater. Although planned low altitude photography was not obtained due to logistical problems, oblique images taken from a fixed wing aircraft were analyzed using convergent photogrammetric techniques. A detailed walking survey of the structure resulted in a well documented data set that can be compared to subsequent surveys. The Ofu Harbor breakwater site will be revisited to gather data to assess the long term response of the structure to its environment. These data will facilitate engineering decisions concerning whether closer surveillance and/or repair of the structure might be requested to reduce its chances of failing catastrophically. The periodic inspection methodology developed and validated for the Ofu Harbor breakwater also may be used to gain insight into other Corps structures.